# null

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Related to null: null space

## null

(nul)
1. insignificant; having no consequence or value.
2. absent or nonexistent.
3. zero; nothing.

## null

Molecular biology
See Null mutation.

Statistics
Completely absent; a set with no members or of zero magnitude. If a field has a value of null, it means that the value is unknown. A null value is not the same as a value of zero, and the difference can be crucial. For example, when calculating the average value of a field among many records where one row contains a zero, the zero gets factored into the average; if the field has a null value, it does not get factored in to the average.

## null

an absence of information, as contrasted with zero or blank or nil, about a value.

null cell
called also null lymphocyte; see null cell.
null hypothesis
a statistical hypothesis which states that one variable has no association with another variable, or set of variables. That is, the observed results can be explained by chance alone.
null lymphocyte
see null cell.
References in periodicals archive ?
Above result satisfies a requirement for the existence of a null horizon in relativity.
The effect of allowing for the possible presence of a null allele
The fitness function depends on the mean square error (MSE) between the desired array factor and estimated array factor given in Equation (6) and the null constraint error given in Equation (7).
Several criticisms of the classical approach are that the null hypothesis under consideration may not be plausible, future evaluation may not be done once the hypothesis is rejected or fails to be rejected, and that prior information (probability) is not considered.
In this subcase, we obtain the following theorem which gives the necessary and sufficient conditions for the null curve in [E.
Let us suppose [phi] = [phi](s) be a null W-curve in the space [E.
Facing these difficulties, Neeleman and Szendroi (2007), not wishing to ignore the language internal evidence that agreement must play a part in the incidence of null subjects, take the view that languages fall into two categories.
Including null values within your data can have an adverse effect when using this data within any mathematical operations.
Specifying a column as not permitting null values can help maintain data integrity by ensuring that a column in a row always contains data.
Besides tagging perfumes, premium spirits and similar high-value products, Flying Null is also targeting the pharmaceutical industry as a prime user of anti-counterfeiting security products, especially for blister packs.
In this application, the phase shifter settings evolve until the antenna pattern has a null in the direction of the jammer.

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